In choosing between repeating a field and repeating a subfield: If the only addition to an existing field is an additional term from the same vocabulary, repeat the subfield. If the vocabulary source differs, or if another associated element differs (such as a range of dates), repeat the field. Overall best practice: repeat the field when needed for clarity. | In choosing between repeating a field and repeating a subfield: If the only addition to an existing field is an additional term from the same vocabulary, repeat the subfield. If the vocabulary source differs, or if another associated element differs (such as a range of dates), repeat the field. Overall best practice: repeat the field when needed for clarity. |